Human induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CMs) enable cardiovascular disease modeling and regenerative research but exhibit substantial heterogeneity and incomplete metabolic maturation. Palmitate (PA) and oleate (OA) can promote aerobic maturation, although responses vary. Despite sex differences in adult cardiac metabolism, sex effects in hiPSC-CMs remain poorly defined.

We assessed sex-dependent metabolic and functional responses in hiPSC-CMs from three male and three female lines treated with PA or OA. Contractile function, aerobic metabolism, and transcriptomic profiles were evaluated.

Sex differences were modest at baseline but pronounced after FA treatment. Male- and female-derived hiPSC-CMs responded differently to PA and OA across contractile, metabolic, and transcriptional measures, indicating that FA identity and sex jointly shape hiPSC-CM phenotypes.

Sex contributes to hiPSC-CM heterogeneity and modulates responses to FA-based maturation. Incorporating sex-specific metabolic and functional regulation may improve the consistency and physiological relevance of hiPSC-CM maturation strategies.